It is known that acute hepatic insufficiency is a serious clinical syndrome that may be caused by various etiologic factors (toxic, viral, vascular occlusion, low flow rate, etc.). These factors all have the common characteristic of causing variable degrees of necrosis of the hepatocytes. In the massive form in which over 80% of the hepatocytes are destroyed the prognosis is unfavourable unless a liver transplant is performed quickly. On the other hand, it is known that a liver transplant cannot always be performed (for example, due to sepsis, or to the advanced age of the patient, etc.) and, even when a transplant is indicated, it cannot always take place due to the shortage of donors.
On the other hand, current support systems, among which the “bio-artificial liver”, are essentially purifying and do not promote hepatic regeneration, but are only useful while waiting for an organ to become available or until the necrotic liver undergoes a process of self-regeneration which would avoid transplant.
Instead, to promote hepatic regeneration the present invention proposes (in a particular embodiment) arterialization of the portal vein, or, in other words, oxygenation of portal blood with arterial blood.
Surgical arterialization of the portal vein has proved efficacious both clinically, where it has been used to solve massive hepatic necrosis secondary to arterial thrombosis after transplant, and in an experimental model in the rat in which massive hepatic necrosis was induced by means of administering carbon tetrachloride.
As will be explained in greater detail hereunder, oxygenation of the portal blood is performed by means of a specific device that can be marketed equipped with a relative kit to be implanted in the body of the patient (see below).
Moreover, on the basis of experimental data, by oxygenating the portal vein according to the present invention, hepatic necrosis is resolved completely within forty-eight hours, although a great improvement can already be observed after twenty-four hours.
It is known that all the blood of the intestine flows through the portal vein. The portal vein (also called “portal trunk”) originates from the union of its roots represented by the superior mesenteric vein and the inferior mesenteric vein, which collect blood from the intestine, and by the splenic vein which instead conveys the blood coming from the spleen. Being venous blood, it is therefore poorly oxygenated. This blood, which, as mentioned, comes from the intestine and the spleen, is metabolized by the liver and returned to the vena cava. Therefore, in the liver as well as the arterial flow route (hepatic artery), there is also a venous flow route (portal vein) and a discharge route (the suprahepatic veins which discharge into the vena cava). The blood reaches the right heart through the vena cava.
It has been experimentally observed that hyperoxygenation of the portal blood stimulates hepatic regeneration. In other words, the liver is an organ capable of regeneration. Therefore, in the presence of necrosis caused by the action of toxic agents, of viral agents or by mushroom poisoning, if oxygenated blood reaches the portal system hepatic necrosis is resolved in 48 hours through triggering of cellular regeneration.
There are two routes through which the liver can be reached:                (1) through the jugular vein; or        (2) by direct injection of the liver.        
It is known that the jugular vein carries blood to the right heart. To reach the portal vein it is possible, through the jugular vein and the right atrium, to reach the suprahepatic vena cava and the suprahepatic veins (usually right or middle). Therefore, a direct link is created with the portal branch (usually right) and the portal trunk.
Arterial blood, taken for example from the femoral artery at the groin, is at high pressure (100-120 mm of mercury) and ends up in a low pressure portal venous system (15-20 mm of mercury), so that a sort of “natural pumping” of arterial blood towards the portal vein is obtained.